Hi everybody

I have a big problem, I buy itcoins but it asks me to scan the private key. I quote "This address is in read-only mode. To spend the funds in this portfolio, please scan your private key.
Or find that private key? thank you

Where are you trying to buy bitcoins?

Sounds like a scam because you should never give away your private key, a BTC address should be enough for them to send BTC to you.

When I have send bitcoins address (because this is an imported address) to "my wallet" they tell me

"This action requires a private key for the address itcoins ....... please scan the QR

Import Export
Multiple Private Key Formats - Mini private keys, Wallet Import Format, Base58, Base64 and Hex.
Watch Only - Watch Only addresses allow you to view transactions at an address without storing the private key in your wallet.
Brain Wallet - Generate A private key from a passphrase.
Import From QR Code - Scan A private key using a webcam.
Import Wallet Files - Vanitygen, blockchain.info and multibit .key files supported.
Export Encrypted or Unencrypted.
JSON RPC Import - Import Export using the bitcoind JSON RPC API
Paper Wallets
Sign Message - Sign a message to prove you own a bitcoin address.
Verify Message - Verify the owner of a bitcoin address.
Import Bitcoin-Qt Wallet - Import keys from a wallet.dat file.

When I have send bitcoins address (because this is an imported address) to "my wallet" they tell me

"This action requires a private key for the address itcoins ....... please scan the QR

You have the app yet you cannot do transactions using that app? What, have you imported a watch-only address? Upon downloading a wallet app, it comes with a private key already, even blockchain.info app has that. It might have been that you are using a wallet that is watch-only and cannot be used to spend coins, only receive coins and you cannot do anything to those coins being received, hence the term "watch-only".

Are there already coins in the address?

Then you never bought bitcoin. An address does not generate itself[1]. Its derived from the private key. Where did you get the address from?

[1] yeah, there are exceptions like burn addresses

How you have generated that bitcoin address? I mean have you generated using some services like bitaddress.org and than you have imported that to blockchain.info wallet? If so than i think you have actually scanned bitcoin address while importing so it remain as watch only address, you should have scanned private key when importing before. Hope you have printed out bitcoin address detail.... If not i think your bitcoin will stuck in that address and you will not have access to it.